摘要
在机载光电转台、多自由度摇摆台等系统中,对于一些运动体与基座间没有确定的回转轴的柔性支撑、并联支撑平台,需要考虑非接触三轴角度测量方法,目前大部分的光电非接触三轴角度测量方案系统复杂,占用空间大,无法适用于如机载、星载等载荷对体积、质量敏感的场景。为此,文中提出了基于双位置敏感探测器(PSD)的非接触三轴角度测量方案,使用准直镜头汇聚、双面反射光楔反射,将光源在两片PSD上汇聚成像,利用PSD上的光斑位置坐标反解出三轴角度。描述了其工作原理以及传感器构成,分析了因两片PSD的相对位置偏移产生的误差,提出了对应补偿方法以减少焊装产生的PSD位置偏移对测量精度的影响。主要对采集的PSD模拟信号值的抖动噪声进行FIR滤波处理,分析了滤波器的相频响应特性,并在MCU中测量相位滞后时间以及滤波器的响应带宽,验证了该数字滤波器在系统内拥有较好的实时传输特性。自准直测量单元总质量为230 g,尺寸为50 mm×50 mm×50 mm。实验结果表明,34阶FIR滤波器将角度测量的误差减小至60%,在±2°测量范围内单轴测量时,方位角、俯仰角、横滚角的误差均方根分别为0.003°、0.007°、0.017°,组合测量时分别为0.006°、0.009°、0.021°,文中所提出的三维测角传感器精度较高,满足机载等场景的使用要求。
Objective In systems such as airborne photoelectric turntables and multi degree of freedom swing tables,threedimensional angle measurement is often required.The methods of angle measurement are divided into contact measurement and non-contact measurement,and different measurement methods need to be selected based on actual application scenarios.For some flexible supports,parallel support platforms,and uncertain rotation axes between the moving object and the base,non-contact measurement methods need to be considered.At present,the common non-contact three-axis angle measurement schemes are complex and occupy a large space,which cannot meet the volume and weight requirements of airborne and spaceborne payload.Therefore,it is necessary to develop a non-contact three-axis angle measurement method with a simple structure and small footprint to meet the needs of different usage environments.Therefore,a non-contact three-dimensional angle measurement system based on two position sensitive detectors(PSD)has been proposed.Methods A three-axis angle measurement system based on dual PSD has been established.The system mainly consists of two parts of an autocollimation measurement unit and a double-sided reflection wedge(Fig.2).The autocollimation measurement unit includes a light source,PSD1,PSD2,autocollimation lens,and subsequent processing circuits.The light beam emitted by the light source converges into parallel light through a collimating lens.And PSD1 and PSD2 receive the light spot converged by the reflected beam and perform signal processing calculations through a processing circuit.The double-sided reflective wedge is designed with a semi-reflective and semi-transparent front surface and a fully reflective rear surface.Its function is to disperse the incident collimated parallel light into two beams and reflect them back into the self-collimating lens,which converges onto the target surfaces of two PSDs to form a light spot.According to the principle of angle measurement,the calibration method of two PSDs is designed to compensate for welding errors,and the FIR filtering algorithm is used to filter the simulated collected signal to improve accuracy.Results and Discussions A three-axis angle measurement system based on dual PSD has been designed,and a calibration experimental system(Fig.5)has been established to calibrate the relative position relationship between two PSDs.The welding error of the relative positions of the two PSDs is compensated through the rotation matrix and translation matrix,and the compensation result is great.A 34th-order FIR filter was designed and simulated,and the experimental results show that the designed filter has a good filtering effect on the actual collected noise signals.The filter is applied to the actual processing MCU for experiments,and the phase frequency response characteristics of the selected filter are analyzed.The test results show that the response bandwidth of the filter is1.31 kHz,which can effectively filter out high-frequency noise signals in the analog voltage signal.The angle measurement experimental system(Fig.13)has been established,and the three-axis angle measurement function of the system has been verified.The system also has high accuracy.Conclusions A non-contact three-axis angle measurement system based on dual PSD is designed.This system has advantages such as simple structure,small size,high accuracy,large measurement range,high bandwidth,non-contact,and insensitivity to axial translation.The rotation matrix,translation matrix,and the designed 34thorder FIR filter obtained from calibrating two PSDs are coded and written into the STM32F4 series microcontroller,and the filter delay is approximately 525μs,which is within an acceptable range.The processing circuit and selected devices designed according to the actual requirements of the project have been experimentally verified.Within a measurement range of±2°,the accuracy of yaw angle measurement reaches 0.006°,pitch angle measurement accuracy reaches 0.009°,and roll angle measurement accuracy reaches 0.021°.The overall autocollimation measurement unit weighs 230 g and has a size of 50 mm×50 mm×50 mm square box.The response frequency of the measurement system can reach 1.15 kHz.This system can measure the three-axis angle in real-time at high speed with high accuracy and small volume,and is suitable for various engineering applications,providing stable and high-speed three-axis angle measurement solutions for airborne,spaceborne,and other conditions.
作者
赵文赫
白杨杨
王劲凯
张立中
Zhao Wenhe;Bai Yangyang;Wang Jinkai;Zhang Lizhong(College of Mechanical and Electrical Engineering,Changchun University of Science and Technology,Changchun 130022,China;National and Local Joint Engineering Research Center of Space and Optoelectronics Technology,Changchun University of Science and Technology,Changchun 130022,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2024年第2期98-108,共11页
Infrared and Laser Engineering
基金
国家自然科学基金项目(U2141231)。
关键词
三轴姿态角度测量
非接触测量
位置敏感探测器
滤波带宽
响应频率
three-axis attitude angle measurement
non-contact measurement
position sensitive detector
filter bandwidth
response frequency
